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Okay well even at 0.2mm layer that's still faster than I recommend and faster than many printers can do (7 mm^3/sec). I'd try lowering the speed to 40mm/sec (3.5mm^3/sec). Here is a table of max speeds for ultimakers - other printers are similar: Here are top recommended speeds for .2mm layers (twice as fast for .1mm layers) and .4mm nozzle: 20mm/sec at 200C 30mm/sec at 210C 40mm/sec at 225C 50mm/sec at 240C So obviously the next question is what temperature are you printing at. So that pattern you see are layers that are partly underextruded and part of the layer looks fine. I would look at the part in slice view if you want to know more and you can pick a layer with the vertical layer scroll and then use the horizontal scroll just above and you can see what the print pattern is - what the order is - so you can know if outer wall is printing clockwise or counter clockwise. Then also in layer view show speeds with color so you can see where it's printing faster and where it's printing slower. I'm going to guess it's printing at different speeds or different line widths on a given layer (infill or inner shell different than outer shell) and the transition from slow speed to fast speed or thin line width to thicker line width means it underextrudes for a bit until the pressure can equalize.

That does not look like 0.4mm layer height. Are you sure that's what you meant? Maybe you mean 0.04mm layer height?

80mm/sec with .4 layer height and .4 layer width - well that's a very thick layer. Multiply those 3 numbers and you get 13.8mm^3/sec. That's a bit beyond what any ultimaker printer can do (what kind of printer do you have). Maybe you should switch to a 0.6 or 0.8 nozzle which allows a much higher printing volume.

I don't see any photo. Did you drag and drop the photo onto your post? Drag and drop works for me.

This is called a torture test for good reason. The filament doesn't get much time. You want to set the travel speed as fast as possible but it's going to string a little no matter what. These strings are pretty easy to remove by hand. One thing you can try is lowering the temperature. A lot. Maybe even as low as 180C but be careful as the filament gets more viscous and you might get underextrusion if you print too fast at 180C. You could also print with a smaller nozzle such as the .25. Make sure fan is at 100% but that's the default so you can't do much there.

PLA has a large printing range from around 170C to around 240C. It is much thicker and more viscous at 170C so the feeder has to work much harder. Like toothpaste. At 240C it is more like honey. So if you want to print faster it helps the extruder if you raise the temperature. But if you want better quality you have to lower the temperature so the filament stays where it is once it leaves the nozzle instead of spilling out, etc. But if you lower the temperature you also have to lower the volume per second so you don't exceed the ability of the feeder to push. If you are printing 40 cubic mm per second you will indeed want the temp at 240C. So for example 0.6mm layer height with 0.8mm line width and 83mm/sec printing speed. But the part will not look very good. Maybe that's fine. But if you want the part to look nice, try 0.3mm layer height, 0.8mm line width and 40mm/sec and 210C. You will get nicer overhangs and walls with less bumps. Yes the printer is sort of "intuitive" if you print with the standard 0.4mm nozzle but when you venture away from the most basic settings you will also have to do more tweaking to get things the way you want. For example if you hate "ringing" you will want to make sure acceleration control and jerk control is enabled (it is by default). But if you care more about dimensional accuracy of your parts you will probably want those turned off.

fyi, the sig file is a cryptographic signature of the main file. If the sig file doesn't match the main file then the printer won't install it. This prevents accidental bricking of the printer and prevents 3rd parties from creating simple firmware installers for the UM3.

Should be "latest.tar.xz" and "latest.tar.xz.sig" I'm guessing you did that step right but double check the names of the files. Probably the printer can't read your USB stick at all. You could put a file on there called a.gcode (doesn't matter what it contains) and go to the print menu to see if it sees your file. If not it probably can't read *anything* on the USB stick. Maybe find another USB stick and don't format it. Or format it for FAT32.

By the way, make sure you also do a retract. If you keep track of the E value (extruder) you can do a retract like this: G0 E1243.123 where the number after the E is the new position to move the extruder to (for UM2 the position is in cubic mm of filament but for UMO, UM3 and S5 it's in linear mm of filament). And of course an un-retract when it gets back to printing again. Also you don't want to pause for a few seconds because even if you only pause for 3 seconds the nozzle will leak (as pla heats up it slowly expands driving filament out) and then that little tiny "sausage" below the nozzle will hang there and when the nozzle moves back into the part it will attach to the side of the part giving you tiny strings sticking out of the print - one on each layer. So you want to take that photo very quickly. It might be best to print a tower next to the part (this feature is built into cura) and do the photo right when it first starts to print the tower. If the tower is near your switch (you can position the tower) then no need to write any plugin at all! The advantage of a tower is there is very little delay from when it finishes a layer on the tower to jump over to the print - it will pick a point as close as possible to the tower to start that layer.

That's great that you know python as plugins are written in python. The simpler kind of plugin is called a "post processing plugin" which works on the gcode that cura just created and does a final step. That's what I recommend. The existing ones can be found here: https://ultimaker.com/en/resources/20442-post-processing-plugins The code for them to see how they are written is here: plugins/PostProcessingPlugin/scripts (what operating system do you use? The main install folder depends on your OS and then go down from there) I think maybe you can put your plugin there but it will get lost when you install a new cura so I think it's recommended to go in the user area which can be found in cura by doing "help" "show configuration folder". You may see a plugins.json file there but I'm not sure what to do at this point. @ctbeke @ahoeben - is there a post processing plugin writing guide somewhere I can link to? I sat in a ctbeke course on doing this but now I don't know where the power point presentation went. ?

>And seems as the bottom is sealed, then the supports would be stuck inside rattling around. Ah. But if you can make the "bottom" or the *neck* level you can uncheck "print top surface" or something like that (I just made that up). I've seen people do this with cups all the time.

>Make Overhang Printable I wasn't familiar with that feature. Cura gets new features faster than I can keep track. Thanks for this - next time I'll know the answer.

I've never seen this but you should know that for a proper uninstall you also want to delete everything in the cura user folder. On a PC I believe that is in the folder %appdata%/cura/ Delete everything in there and then start cura up again and it will be like a fresh install of cura.

Make all the "mesh fixes" vislbe and make sure they are all unchecked. There's 6 of them. One of them may be making your head solid again. It's much easier to have your head model be solid and to set infill to 0% and then you can set your wall width to however thick you want. It will print much faster this way also. I'm still not sure what is going on with the top of the head. The head looks like it is raised up off the bed yet there is still something touching the glass.

In a text editor it's pretty easy to add these lines with a recorded macro. Search for "Z" go to end of line, insert gcodes. Repeat macro for every layer. The best way to do this would be a plugin. Do you know a little python? It's not hard to write cura plugins. Are you going to take a photo on every layer completion? To make a sped up video?

Are you sure you didn't assemble the feeder backwards? Look at pictures. If you download tinker firmware it lets you toggle the direction of all the steppers right from the menu system. tinker firmware is great and has all kinds of wonderful features such as "continue from failed print". I recommend version 16.01 here as it seems to be the most stable: https://github.com/TinkerGnome/Ultimaker2Marlin/releases/ (scroll way way down).

UMO can easily get to 250C as I've printed ABS with it. The problem is likely that your fan is blowing too much onto the nozzle (or bouncing off the glass and back to the nozzle). Try setting the fan to 30% and try angling the shroud more downwards. But yes you can also get a higher power heater. Do you have a UMO with the 19V supply or a UMO+ with the 24V supply? It matters when you choose a heater as the wattage depends on the voltage. And if you get more than 35W you will probably have to adjust PID a little but it's not hard and we can explain how to do that if your temperature is oscillating too much.

I've never tried pva when I used 0.25mm nozzle. I'm wondering if there is a bug. What did cura choose for the line width for the second core? Ideally you want a line width around 0.2 to 0.25 for the .25mm core and a line width of 0.35 to 0.4mm for the BB 0.4mm core.

If my advice isn't helpful please show a few photos of what you are talking about. How big your part is and how it looks when printed.

What is the diameter of your cylinder @SImona91 ? If it truly doesn't have time to cool down (it would have to be very small - maybe 1cm or smaller?) then you should print 2 or 3 of these objects side by side. As it prints the layer of one cylinder the other 2 are cooling down. Generally with nylon you want things very hot. So heated bed at 100C or higher. Enclose the printer. Fan between 0 and 3% for UM3 and 0 to 30% for UM2. But you might want to put the fan at the high end of that range (maybe even 5% fan for um3 and 40% for Um2). The bigger problem with nylon is that it absorbs water right out of the air. You have to keep it very dry. And if you leave it out for a few days you may have to dry it again (I usually dry nylon filament on the heated bed at 110C for 2 to 6 hours). If nylon gets moisture then when you print it will come out snowy white instead of clear and it will sizzle and pop as it prints.

I have only ever bought 4gb cards because that is what UM sells even though they cost a few dollars more I wanted to be safe. Actually I just checked and one of them has 8gb and is formatted for 8gb FAT32 and it works (I didn't buy that one - it came for free when I bought a used um2go). So I would try partitioning as geert_2 suggests but also ask other monoprice owners - there's a (tiny) possibility that they force you to buy SD cards only from them and have some secret file or something on the SD card that the monoprice expects. What format is the SD card formatted with that works?

You keep saying "burned" but heat has nothing to do with your problem. It's mechanical. Maybe the wires are too stiff. Maybe they weren't tied down well with that black part with the 2 screws. Maybe the cable was upside-down. All I know is the problem is mechanical. Too much force against that black connector versus how well it was soldered on. Maybe it wasn't soldered on well but I can see in the picture the solder looks pretty good. maybe the cable is too short such that when the platform moves all the way up the cable is pulling very hard. Do you have a friend who has soldering experience? Maybe a friend of a friend? I could fix this in 20 minutes - it's not hard. Ask around. If you watch someone fix this and see how easy it is then you can do it yourself next time. Your picture makes you look like a manager - maybe someone who works for you should learn how to solder.

PVA and Nylon need to be kept quite dry. Especially nylon. I don't leave my PVA on the printer overnight if it's not printing. I keep it in a sealed bag. Whenever I get new filament with new dessicant I move the dessicant packet to my nylon and pva bags as the PLA really doesn't need it. You can tell if PVA is too wet (or any material) because it sizzles and pops while printing and comes out more snowy than clear (lots of micro steam bubbles). You can "repair" the PVA by heating it but it gets soft at 65C so I wouldn't heat it beyond 60C. You can put it on a heated bed at 60C with a towel over it for 10 or 20 hours. I suspect that will work. Assuming that's the problem. PVA is annoying in that if it gets too dry it also fails (gets brittle). 60C should be safe. You want I think around 10-20% humidity. Using this slider: http://www.dpcalc.org/ Let's assume in your building the temp is 20C and humidity is 60% then the dew point is 12C. Crank temp up to 60C using the calculator above and slide the humidity down until you get 12C dewpoint still and your new humidity is about 7% (heating air won't change the dewpoint but it lowers the humidity). I'm not sure this math is the correct way to calculate things for drying filament but it's what I use. That should be safe I would hope. It just might take many hours for the water to escape the pva - especially on the inner turns of filament deep in the spool. Anyway I've used this trick (heat it to 110C for nylon) to dry nylon to great success.

Well first of all it's fine to set the temp manually in the tune menu after it starts printing the skirt or brim. It should stick with that temperature as long as there are no temperature commands in the gcode (which is extremely unlikely or you wouldn't be having this issue). So on the UM2 the nozzle temp is associated with both the material and the nozzle size. For PLA, I think the defaults are around 210C for the 0.4mm nozzle and possible 240C is for the 0.8mm nozzle? Are you using a 0.8mm nozzle? The cura/um2 defaults work best for me with the 0.4mm nozzle. If you want to print with a 0.8mm you may have to override a few things. Fixing this permanently is tricky. In the materials menu there is an option to write the materials settings to a file on the SD card then you can bring that to a computer and edit it with a text editor (like notepad on the pc) and fix the temperatures associated with your material (I assume PLA). 1) Are you using a 0.8mm nozzle? 2) Did you mention that you are using a 0.8mm nozzle possibly in cura? 3) If you look at the gcode file with an editor - near the top it should say the nozzle size that cura thinks you will be using. What does it say? That's where Marlin (the firmware inside the UM2) get's its information about what nozzle you are using.

@JCD - Interesting idea but won't work. As steve says it's related to the fact that plastics have a relatively high temperature expansion constant and plastic shrinks as it cools. Particularly when it goes from clay-like softness (about 55C for PLA ) to room temperature. But also partly when it is still maleable from 55C to around 100C. Strengthening the corners doesn't help because the problem isn't at the upper layer corners. The problem is underneath the part. Those long walls of that box print in your drawing are shrinking and pulling inward. The bottom layer is stuck to the bed. As the upper layers pull inward there is an incredible lifting force at the bottom. All of that force is concentrated in a tiny pixel sized spot at the corner. So one fix is rounded corners. That spreads the load onto the whole curve. Brim is an even better fix because if you can get a vacuum under there it's really hard for the corner to lift without some air leaking in there and the brim prevents air from getting in there in addition to holding it down mechanically. I have a whole 15 minute video that talks about these exact issues and much more.